This invention relates generally to the field of internal combustion engines, and more particularly to a method and apparatus for extending the operating interval between oil changes for an internal combustion engine.
The reliability of an internal combustion engine is directly affected by the condition of the lubricant used in the engine. It is known to provide an oil filter for removing particulate matter from an engine's lubricant during the normal operation of the engine. Such oil filters must be changed regularly as they become clogged with particulate matter. Filtering of the oil is effective for removing particulate matter, however, the entire volume of the lubricant must be changed periodically in order to maintain a desired level of additives contained within the lubricant. Thus it is known that, for most internal combustion engine applications, there is a recommended frequency for changing the lubricant. For example, the manufacturers of many automobiles recommend that the lubricating oil and filter be changed after 3,000 miles of operation. The assignee of the present invention supplies locomotives driven by diesel engines. Current operating recommendations for such locomotive engines require that the engine lubricating oil be changed quarterly. An oil change on a locomotive engine requires that the locomotive to be taken out of service Thus, the interval between recommended oil changes for an internal combustion engine has an adverse impact on the overall availability of the engine for productive operation. In particular, as the reliability of locomotive components continues to increase, the engine oil change requirement may become a limiting event defining the maximum achievable on-train availability for a locomotive.
Periodic engine lubricant changes also generate a large volume of hazardous waste that must be disposed of and/or reprocessed. The operators of large fleets of internal combustion driven vehicles are faced with a considerable expense for the proper disposal of the spent crankcase oil for the entire fleet.